1. Field of the Invention
The invention relates to a method and a configuration for recording and transmitting data between a transmission unit having an antenna and a measurement module having at least one sensor for recording measured variables, including biological variables.
Methods and arrangements according to the invention are used in particular for on-line monitoring and detecting measured variables or biologic reactions, particularly the electric properties of cell cultures.
Typically, for determining biological properties of a sample, the impedance of this sample is detected at one or more predetermined frequencies. By a plurality of impedances measured at different frequencies, one can draw conclusions on the biologic properties of the sample. To make measurement simple and cost effective, one can provide that the measurement modules, wherein the biological samples are, and the transmission units, which transfer the measured data to a central data processing unit, are realised as separate units. For simple transmission between the transmission unit and the measurement module, wireless data transmission methods can be employed, particularly RFID transmission methods. In a preferred manner, one can provide that the measurement modules are realised as passive RFID components, i.e. that the energy supply of the measurement modules is effected over an electromagnetic signal emanating from the transmission unit, an intermediate storage of energy being effected within the measurement module.
An essential problem of the prior art consists in that the measurement of the impedance of the biologic samples as well as the transmission of measured data are realised by means of quickly changing electromagnetic fields. For this reason, interferences may occur during recording of the measured data, which are caused by the transmission of measured data being already measured before, or by the simultaneous transmission of energy.
2. Brief Summary of the Invention
The invention has the object to solve the above-mentioned problems and to provide a method and a measuring arrangement which overcome said problems.
With the foregoing and other objects in view there is provided, in accordance with the invention a method for recording and transmitting data between a transmission unit having a first antenna and a measurement module having at least one sensor for recording measured variables, including biological variables, and transforms the measured variables into electrical signals and a measuring amplifier coupled to the sensor. The method includes performing a bidirectional transmission of the data between the measurement module and the transmission unit, disposed in a near range of the measurement module, using a second antenna situated on the measurement module. Via a reception unit coupled to the second antenna, electromagnetic energy of a signal present at the second antenna is transformed. The electromagnetic energy is immediately stored and made available in a form of a voltage level at an output. The stored electromagnetic energy is delivered to the sensor and the measuring amplifier as a current supply. Components of the measuring module are controlled via a central data processing unit of the measurement module, while being supplied with the electromagnetic energy stored in the reception unit. The central data processing unit further processes the measured signals of the sensor and communicates with the transmission unit. The first antenna of the transmission unit is set to be inactive for a time period of a determination of the measured variables by the sensor. The setting to inactive is effected at an instigation of the measurement module, which signals to the transmission unit that a storing unit, connected to the reception unit, is fully charged and further signals from the transmission unit should be stopped in a sense of a disturbance-free measurement.
In addition the invention relates to a configuration containing a measurement module, and a transmission unit having a first antenna and an antenna driver for controlling the first antenna. The transmission unit transmits data by use of the first antenna to the measurement module and processes the data received from the measurement module by use of the first antenna. The measurement module contains at least one sensor for recording measured variables, a measuring amplifier coupled to the sensor, a second antenna for bidirectional transmission of the data between the measurement module and the transmission unit disposed in a near range of the measurement module, and a reception unit having an output and coupled to the second antenna. The reception unit transforms and intermediately stores electromagnetic energy of a signal present at the second antenna and puts the electromagnetic energy available in a form of a voltage level existing at the output, and delivers the stored electromagnetic energy to the sensor and to the measuring amplifier as a current supply. A central data processing unit supplied by the electromagnetic energy stored in the reception unit, controls components of the measurement module. The central data processing unit further processes measured signals of the sensor and communicates with the transmission unit. The antenna driver has a circuit for timely limited stopping or for electrical inactivation of the first antenna when receiving a stop signal emitted by the second antenna.
The method also includes the following steps. Setting the first antenna to be active for transmitting the electromagnetic energy to the reception unit, transmitting the electromagnetic energy between the first antenna and the second antenna, and storing the electromagnetic energy in the measurement module. After transmission of a predetermined amount of the electromagnetic energy, transmitting or transferring a control pulse, generated by the measurement module, to the transmission unit, by which the first antenna is set inactive for a predetermined time period. During the predetermined time period, effecting the measurement of the measured variables to be determined. After the end of the predetermined time period, setting the antenna of the transmission unit to be active again. After an end of the measurement, transmitting measured data in coded form from the measurement module to the transmission unit. The method may include a step of after an end of the predetermined time period transmitting the measured data in coded form from the measurement module to the transmission unit.
An essential advantage of the method according to the invention and of the arrangement according to the invention consists in that during detecting the measured variables by the measurement module, no interferences occur between the electromagnetic signal required for measurement and the signal for the transmission of data or energy. Thus, accuracy and the signal-to-noise ratio (SNR) of the measurement is greatly improved, wherein particularly the quality of the impedance measurement is particularly greatly improved in those frequency bands or their harmonic waves or sub-harmonic waves, which coincide with the frequency band that is employed for data transmission. Thus, the invention avoids interferences between in the near field between antennas used for transmission of data and energy, and the components provided for determining the measured variables on the measurement module.
In accordance with an added mode of the invention, the sensors are used to determine an impedance of a sample situated in the measurement module at a predetermined number of frequencies and therefore a particularly precise assertion can be made on the character of biological samples.
With the features of the invention, a particularly simple course of procedure is warranted, which comprises a high failure tolerance and increases the stability of the measurement procedure.
An arrangement where the transmission unit has a plurality of first antennas and a plurality of bidirectional antenna drivers, and each of the bidirectional antenna drivers is connected to each of the first antennas and the measurement module is one of a plurality of measurement modules with each of the measurement modules having a separate second antenna allows integration of a plurality of measurement modules on a transmission unit in common in a simple manner.